title: Genetic parameters for ultrasonic fat thickness of Japanese Shorthorn cattle.
abstract: Records of performance testing from 309 Japanese Shorthorn bulls were used to estimate genetic parameters for ultrasonic fat thickness. Young bulls were tested for 140 days from 9 months of age. Backfat was measured by ultrasound at six positions on each side, from shoulder to loin, at a constant weight of 470 kg. Four of the positions were approximately 10 cm from the mid-line and were defined as upper positions. Two positions were 25 cm from the mid-line and were defined as lower positions. Variance components were estimated by restricted maximum likelihood, using canonical transformation under a multi-trait animal model. Heritabilities (h(2) ) from a single measurement were 0.32-0.48 on upper positions and 0.37-0.27 on lower positions. Corresponding positions on each side of the animal showed very high genetic correlations, from 0.94 to 0.99. The estimated h(2) values of the sum of measurements of four left and right upper positions were 0.52 on both sides. The sum of measurements from eight upper positions showed the highest h(2) , 0.55, and genetic correlations among these summed measurements were nearly 1. Genetic correlations between average daily gain and all fat measurements were mostly slightly negative. The estimated h(2) value for daily gain was 0.44. ZUSAMMENFASSUNG: Genetische Parameter für ultraschallgemessene Fettdicke japanischer Shorthorn Rinder Die Messungen an 309 japanischen Shorthorn Bullen wurden zur Schätzung herangezogen. Diese waren von 140 Tagen bis 9 Monate Alter einer Mastleistungas prüfung unterzogen worden. Ultraschall Fettdicke wurde an 6 Positionen von Schulter bis Lende bei 470 kg Gewicht erhoben, vier ungefähr 10 cm der Mittellinie werden als obere, zwei 25 cm entfernt als untere Position definiert. Die Varianzkomponenten wurden nach kanonischer Transformation auf der Basis eines Mehr-Merkmalmodells mittels restringiertier Maximum Likelihood geschätzt. Heritabilitäten für Einzelmerkmale waren für obere Positionen 0,32 bis 0,48, fü untere 0,37 bis 0,27, die genetischen Korrelationen waren zwischen 0,94 und 0,99. Die Heritabilität für die Summe der vier oberen Positionen an jeder Seite war 0,52, die für alle acht oberen Positionen 0,55. Genetishce Korrelationen zwischen Tageszuwachs und allen Fettdicken waren meistens schwach negativ, die Heritabilität für ersteren 0,44.
authors.affiliation: National Institute of Agrobiological Resources, Kan-nondai, Tsukuba, Japan Institute of Animal Breeding and Husbandry, University of Kiel, Germany Tohoku National Agricultural Experiment Station, Shimo-kuriyagawa, Morioka, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Nagamine
authors.forename: R
authors.initials: R
authors.lastname: Roehe
authors.forename: T
authors.initials: T
authors.lastname: Awata
authors.forename: E
authors.initials: E
authors.lastname: Kalm